CLU and Alzheimer disease: Natalya et al. (2013) found that the influence of CLU genotype was found to be higher in the subjects older than 50 years old. Fennemanotestine et al. (2011) found that presence of APOEε4 was associated with thinner frontal cortex in middle age adults. However, all the subjects were middle-aged, and the differences in image representation might be small, which could not fully explain the differences in gene effects. Secondly, ε2 genotype was reported as a protective gene for delayed AD, the influence of ε2 was not further observed in this study.